Polypropylene material, polypropylene beta nucleating agent and preparation method of polypropylene beta nucleating agent

Abstract

The invention discloses a polypropylene material, a polypropylene beta nucleating agent and a preparation method thereof, and belongs to the technical field of fine chemical engineering. The polypropylene beta nucleating agent has a structural formula as shown in a formula I: # imgabs0 #, p represents any integer from 0 to 7, and R is selected from any one of hydrogen, halogen, nitryl and amino; m is any one of magnesium and calcium. In addition, the invention also provides a preparation method of the polypropylene beta nucleating agent, and the preparation method comprises the following steps: heating a raw material A and a raw material B in an ethanol solution to prepare a compound as shown in a formula II; dissolving the compound as shown in the formula II in THF-MeOH-H2O, then adding LiOH.H2O, and heating to obtain a compound as shown in a formula III; and mixing the compound as shown in the formula III with alkali liquor, and dropwise adding an alkaline earth metal salt solution under a heating condition to obtain the polypropylene beta nucleating agent. The invention provides a novel polypropylene beta nucleating agent, and the beta crystal form nucleation efficiency is up to 90% or above.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical industry, and in particular to a polypropylene material polypropylene beta nucleating agent and a preparation method thereof. Background Art

[0002] In 1954, chemist Natta first synthesized a stereospecific polymer (polypropylene, PP) with a highly regular molecular structure, high strength and high melting point. Montecatini realized its industrialization in 1957. Due to the excellent properties of PP, such as good mechanical properties, non-toxicity, low relative density, heat resistance, chemical resistance and easy processing and molding, its production has developed rapidly and has become the fastest growing and most active new variety development substance among the five major general synthetic resins. However, isotactic polypropylene (iPP) has defects such as high crystallinity and poor impact resistance, which restricts its further development and application. Adding nucleating agents to improve the performance of polypropylene is a commonly used method in industrial production.

[0003] Polypropylene β-nucleating agent affects the toughness of polypropylene by converting α crystals in polypropylene into β crystals, improving the impact strength and heat deformation temperature of polypropylene products, and also giving polypropylene products a good porous structure. However, while improving the toughness and impact strength and other properties, due to the high content of β crystal and too little α crystal, its rigidity usually decreases to a certain extent. Therefore, from the perspective of practical application and nucleation mechanism, it is urgent to develop a polypropylene β-nucleating agent with a novel structure. Summary of the invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies, provide a polypropylene material, a polypropylene β nucleating agent and a preparation method thereof, and solve the technical problem of proposing a new polypropylene β nucleating agent with significant β crystal nucleation efficiency in the prior art.

[0005] In order to achieve the above technical purpose, the technical solution of the present invention provides a polypropylene β-nucleating agent, wherein the polypropylene β-nucleating agent has a structural formula shown in Formula I:

[0006]

[0007] Wherein, p represents any integer from 0 to 7,

[0008] R is selected from any one of hydrogen, halogen, nitro, and amino;

[0009] M is either magnesium or calcium.

[0010] In any embodiment, the polypropylene β-nucleating agent is one or more of the following compounds:

[0011]

[0012] In addition, the present invention also provides a method for preparing the above-mentioned polypropylene β-nucleating agent, comprising the following steps:

[0013] S1, raw material A and raw material B Heating in ethanol solution to prepare the compound of formula II

[0014] S2, dissolving the compound of formula II in THF-MeOH-H2O, then adding LiOH . Heating with H2O gave the compound of formula III

[0015] S3, mixing the compound of formula III with alkali solution, and adding alkaline earth metal salt solution dropwise under heating conditions to obtain the polypropylene β nucleating agent.

[0016] In any embodiment, in step S1, the molar ratio of the raw material A to the raw material B is 1:(1-1.2); and / or, in step S1, the heating temperature is 75-80°C, and the heating time is 0.5-2h.

[0017] In any embodiment, in step S2, the compound of formula II and the LiOH . The molar ratio of H2O is 1:(1-1.2); and / or, in step S2, the volume ratio of THF, MeOH and H2O in the THF-MeOH-H2O is 4:(1-2):(1-2).

[0018] In any embodiment, in step S2, the heating temperature is 45-50° C., and the heating time is 6-8 hours.

[0019] In any embodiment, in step S3, the heating temperature is 60-80° C., and the heating time is 2-4 hours.

[0020] In any embodiment, in step S3, the alkaline earth metal salt in the alkaline earth metal salt solution is one or more of alkaline earth metal nitrates or alkaline earth metal hydrochlorides; and / or, in step S3, the alkali solution is a sodium hydroxide solution.

[0021] In any embodiment, in step S3, the alkaline earth metal nitrate is calcium nitrate or magnesium nitrate, and the alkaline earth metal hydrochloride is calcium chloride or magnesium chloride.

[0022] In addition, the present invention also provides a polypropylene material, comprising the above-mentioned polypropylene β-nucleating agent or the polypropylene β-nucleating agent prepared by the above-mentioned preparation method.

[0023] Compared with the prior art, the beneficial effects of the present invention include: the present invention provides a new polypropylene β nucleating agent, the β crystal nucleating efficiency is remarkable, and the β crystal nucleating efficiency is as high as more than 90%. DETAILED DESCRIPTION

[0024] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] If there is no special explanation, the "include" and "comprising" mentioned in this application are open-ended or closed-ended. For example, the "include" and "comprising" may mean that other components not listed may also be included or included, or may only include or include the listed components.

[0026] If not specifically stated, in this application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0027] This specific embodiment provides a polypropylene β-nucleating agent, and the polypropylene β-nucleating agent has a structural formula shown in Formula I:

[0028]

[0029] Wherein, p represents any integer from 0 to 7,

[0030] R is selected from any one of hydrogen, halogen, nitro, and amino;

[0031] M is either magnesium or calcium.

[0032] In some embodiments, the polypropylene β-nucleating agent is one or more of the following compounds:

[0033]

[0034] This specific embodiment also proposes a method for preparing the above-mentioned polypropylene β-nucleating agent, comprising the following steps:

[0035] S1, raw material A and raw material B Heating in ethanol solution to prepare the compound of formula II The molar ratio of the raw material A to the raw material B is 1:(1-1.2);

[0036]

[0037] S2, dissolving the compound of formula II in THF-MeOH-H2O, then adding LiOH . H2O, heated at 45-50°C for 6-8h to obtain the compound of formula III The volume ratio of THF, MeOH and H2O in the THF-MeOH-H2O is 4:(1-2):(1-2);

[0038]

[0039] S3. Mix the compound of formula III with alkali solution, add alkaline earth metal salt solution dropwise under heating conditions at 60-80° C. to react for 2-4 hours to obtain the polypropylene β nucleating agent; the alkaline earth metal salt in the alkaline earth metal salt solution is one or more of alkaline earth metal nitrates or alkaline earth metal hydrochlorides, the alkaline earth metal nitrate is preferably calcium nitrate or magnesium nitrate, and the alkaline earth metal hydrochloride is preferably calcium chloride or magnesium chloride; and the alkali solution is sodium hydroxide solution.

[0040] This specific embodiment also provides a polypropylene material, including the above-mentioned polypropylene β-nucleating agent or the polypropylene β-nucleating agent prepared by the above-mentioned preparation method.

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] In the present invention, reference is made to “some embodiments”, “this embodiment”, examples, etc., which describe a subset of all possible embodiments, but it can be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0043] If similar descriptions of "first / second" appear in the application documents, the following instructions are added. In the following description, the terms "first\second\third" are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments described herein can be implemented in an order other than that described herein.

[0044] In this embodiment, the term "and / or" is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, object A and / or object B may represent three situations: object A exists alone, object A and object B exist at the same time, and object B exists alone.

[0045] Example 1

[0046] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0047] a. Dissolve raw material A (1,8-naphthalene anhydride, 10 mmol) and raw material B (ethyl aminoacetate, 12 mmol) in 50 mL of anhydrous ethanol, heat and reflux for 1.0 h, cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain intermediate II (N-ethoxycarbonylmethyl-1,8-naphthaleneimide) as a white solid with a yield of 98%;

[0048] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 50°C for 8 h, concentrated to half of the original volume, added 1M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III (N-carboxymethyl-1,8-naphthalimide) as a white solid with a yield of 95%;

[0049] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution, heat it to 80°C, drop 2 times the molar amount of calcium nitrate solution, react for 2 hours, cool, filter, and dry to obtain Formula I (1,8-naphthaleneimide-aminoacetic acid calcium, A1), a white solid, with a yield of 85%. The hydrogen spectrum and high-resolution mass spectrum data of 1,8-naphthaleneimide-aminoacetic acid calcium are as follows:

[0050] 1H NMR(400MHz, DMSO-d6)δ:8.50-8.48(m,4H),7.87-7.85(m,2H),3.79(s,2H)ppm; HRMS(ESI+)calcd for C 28 H 17 CaN2O8[M+H] + 549.0594, found 549.0612.

[0051] Example 2

[0052] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0053] a. Dissolve raw material A (4-chloro-1,8-naphthalene anhydride, 10 mmol) and raw material B (ethyl 3-aminopropionate, 12 mmol) in 50 mL of anhydrous ethanol, heat under reflux for 1.0 h, cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain an intermediate of formula II;

[0054] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 45°C for 6 h, concentrated to half of the original volume, added 1M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III as a white solid with a yield of 95%;

[0055] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution, heat it to 75°C, drop 2 times the molar amount of calcium nitrate solution, react for 2.5 hours, cool, filter, and dry to obtain Formula I (4-chloro-1,8-naphthaleneimide-aminopropionic acid calcium, A2), a white solid, with a yield of 82%. The hydrogen spectrum and high-resolution mass spectrum data of 4-chloro-1,8-naphthaleneimide-aminopropionic acid calcium are as follows:

[0056] 1 H NMR(400MHz, DMSO-d6)δ:8.54-8.52(m,2H),8.39-8.37(d,J=3Hz,1H),8.04-8.01(m,1H),7.72 -7.69(d,J=3Hz,1H),3.80-3.78(t,J=8Hz,2H),2.72-2.69(t,J=8Hz,2H)ppm; HRMS(ESI+)calcd for C 30 H 19 CaCl2N2O8[M+H] + 645.0128, found 645.0120.

[0057] Example 3

[0058] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0059] a. Dissolve raw material A (4-bromo-1,8-naphthalene anhydride, 10 mmol) and raw material B (ethyl aminoacetate, 12 mmol) in 50 mL of anhydrous ethanol, heat under reflux for 1.0 h, cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain an intermediate of formula II;

[0060] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 45°C for 7 h, concentrated to half of the original volume, added 1M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III as a white solid with a yield of 95%;

[0061] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution, heat it to 70°C, drop 2 times the molar amount of magnesium nitrate solution, react for 3 hours, cool, filter, and dry to obtain formula I (4-bromo-1,8-naphthaleneimide-aminoacetic acid magnesium, A3), a white solid, with a yield of 80%. The hydrogen spectrum and high-resolution mass spectrum data of 4-bromo-1,8-naphthaleneimide-aminoacetic acid magnesium are as follows:

[0062] 1 H NMR(400MHz, DMSO-d6)δ:8.56-8.50(m,2H),8.31-8.26(m,2H),8.03-8.01(d,J=3Hz,1H),3.79(s,2H)ppm; HRMS(ESI+)calcd for C 28 H 15 Br2 MgN2O8[M+H] + 688.9029,found688.9025.

[0063] Example 4

[0064] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0065] a. Dissolve raw material A (4-nitro-1,8-naphthalene anhydride, 10 mmol) and raw material B (ethyl 3-aminopropionate, 12 mmol) in 50 mL of anhydrous ethanol, heat under reflux for 1.0 h, cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain an intermediate of formula II;

[0066] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 50°C for 6 h, concentrated to half of the original volume, added 1M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III as a white solid with a yield of 95%;

[0067] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution, heat it to 60°C, drop 2 times the molar amount of magnesium nitrate solution, react for 4 hours, cool, filter, and dry to obtain formula I (4-nitro-1,8-naphthalene imide-aminopropionic acid magnesium, A4), a light yellow solid, with a yield of 82%. The hydrogen spectrum and high-resolution mass spectrum data of 4-nitro-1,8-naphthalene imide-aminopropionic acid magnesium are as follows:

[0068] 1 H NMR(400MHz, DMSO-d6)δ:9.20-9.17(d,J=2Hz,1H),8.96-8.94(d,J=2Hz,1H),8.56-8.51(m,2H ),8.03-7.99(m,1H),3.77-3.75(t,J=8Hz,2H),2.67-2.60(t,J=8Hz,2H)ppm; HRMS(ESI+)calcd for C 30 H 19 MgN4O 12 [M+H] + 651.0833, found 651.0825.

[0069] Example 5

[0070] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0071] a. Dissolve raw material A (1,8-naphthalene anhydride, 10 mmol) and raw material B (ethyl 4-aminobutyrate, 12 mmol) in 50 mL of anhydrous ethanol, heat under reflux for 1.0 h, cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain an intermediate of formula II;

[0072] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 50°C for 6 h, concentrated to half of the original volume, added 1M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III as a white solid with a yield of 95%;

[0073] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution, heat it to 60°C, drop 2 times the molar amount of magnesium nitrate solution, react for 3 hours, cool, filter, and dry to obtain formula I (1,8-naphthaleneimide-aminobutyric acid calcium, A5), a white solid, with a yield of 80%. The hydrogen spectrum and high-resolution mass spectrum of 1,8-naphthaleneimide-aminobutyric acid calcium are as follows:

[0074] 1 H NMR(400MHz, DMSO-d6)δ:8.52-8.46(m,4H),7.87-7.82(m,2H),3.74-3.70(t,J=7Hz,2H),2.34-2.30(t,J=8Hz,2H),1.96-1.90(m,2H)ppm; HRMS(ESI+)calcd for C 32 H 25 CaN2O8[M+H] + 605.1220, found 605.1215.

[0075] Example 6

[0076] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0077] a. Dissolve the raw material A (4-chloro-1,8-naphthalene anhydride, 10 mmol) and the raw material B (5-aminovaleric acid ethyl ester, 12 mmol) in 50 mL of anhydrous ethanol, heat and reflux for 1.0 h, then cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain the intermediate II;

[0078] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 45°C for 8 h, concentrated to half of the original volume, added 1M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III;

[0079] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution. Heat to 75° C. and drop 2 times the molar amount of magnesium nitrate solution into the mixture for reaction for 3.5 h. Cool, filter and dry to obtain the formula I (4-chloro-1,8-naphthaleneimide-aminovaleric acid magnesium, A6), a white solid with a yield of 85%. The hydrogen spectrum and high-resolution mass spectrum data of 4-chloro-1,8-naphthaleneimide-aminovaleric acid magnesium are as follows:

[0080] 1H NMR(400MHz,DMSO-d6)δ:8.54-8.50(m,2H),8.39(s,1H),8.00-7.96(m,1H),7.65(s,1H),3 .16-3.12(t,J=7Hz,2H),2.23-2.19(t,J=7Hz,2H),1.60-1.50(m,4H)ppm; HRMS(ESI+)calcd for C 34 H 27 MgN2O8[M+H] + 685.0978, found 685.0982.

[0081] Example 7

[0082] This embodiment provides a polypropylene β-nucleating agent, which is prepared by the following steps:

[0083] a. Dissolve raw material A (4-bromo-1,8-naphthalene anhydride, 10 mmol) and raw material B (6-aminocaproic acid ethyl ester, 12 mmol) in 50 mL of anhydrous ethanol, heat under reflux for 1.0 h, cool, filter, wash, recrystallize from ethanol-water solution, and dry to obtain an intermediate of formula II;

[0084] b. Weigh the intermediate II (5 mmol) and dissolve it in THF / MeOH / H2O 4:1:1 (v / v / v), then add LiOH . H2O (10.0 mmol), heated to 50°C for 7 h, concentrated to half of the original volume, added 1 M HCl to neutralize to neutrality, a large amount of precipitate was produced, filtered and dried to obtain the intermediate III;

[0085] c. Weigh the intermediate III (3 mmol) and dissolve it in an equimolar amount of sodium hydroxide solution, heat it to 60°C, drop 2 times the molar amount of calcium nitrate solution, react for 4 hours, cool, filter, and dry to obtain formula I (4-chloro-1,8-naphthaleneimide-aminocaproic acid calcium, A7), a white solid, with a yield of 85%. The hydrogen spectrum and high-resolution mass spectrum data of 4-chloro-1,8-naphthaleneimide-aminocaproic acid calcium are as follows:

[0086] 1H NMR(400MHz, DMSO-d6)δ:8.54-8.50(m,2H),8.38-8.36(d,J=3Hz,1H),7.98-7.94(m,1H),7.67-7.65(d,J=3Hz,1H ),3.16-3.12(t,J=7Hz,2H),2.21-2.18(t,J=8Hz,2H),1.56-1.50(m,4H),1.32-1.28(m,2H)ppm; HRMS(ESI+)calcd for C 36 H 31 CaCl2N2O8[M+H] + 729.1067, found 729.1059.

[0087] Test Case

[0088] The nucleation efficiency of the polypropylene β-nucleating agent in the above Examples 1-7 was tested.

[0089] The β-crystal content in polypropylene was determined by differential scanning calorimetry (DSC). Specifically, metal indium was used for temperature correction and thermal hysteresis correction; the sample was quickly heated from 80°C to 200°C under nitrogen protection, and the temperature was kept constant for 5 minutes to eliminate the thermal history. The sample temperature was lowered from 200°C to 80°C at a cooling rate of 10°C / min, and heated to 200°C again at a scanning rate of 10°C / min, and the second melting process of the sample was recorded. The β-crystal melting peak that appears in the range of 150-155°C is T β , the melting enthalpy is ΔH β The melting peak of the α-crystal in the range of 160-170°C is T α , the melting enthalpy is ΔH α ; β-crystal content K β The calculation results are listed in Table 1.

[0090] It should be noted that the sample in the above test refers to a mixture of the β-nucleating agent in the above embodiment added to polypropylene (PP) at a weight of 0.01 wt% to 0.10 wt% of the mass of polypropylene; wherein D1 in the following Table 1 is the nucleating agent added in the prior art

[0091]

[0092]

[0093] In formulas (1) and (2), ΔH β is the melting enthalpy of β-crystalline polypropylene, ΔH α is the melting enthalpy of α-crystalline polypropylene; is the standard melting enthalpy of polypropylene, is 168.5 J / g, It is 177.0J / g.

[0094] Table 1 β-crystal content of PP after modification by A1-A7 and D1

[0095]

[0096] As can be seen from Table 1, when the new polypropylene β-nucleating agent (A1-A7) is added in an amount of 0.01-0.10wt% in PP, the β-crystal content in PP can reach more than 90%, indicating that the nucleating efficiency of the nucleating agent is significant and can effectively induce the formation of β-crystal PP.

[0097] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A polypropylene β-nucleating agent, characterized in that: The polypropylene β nucleating agent has a structural formula shown in Formula I: Wherein, p represents any integer from 0 to 7, R is selected from any one of hydrogen, halogen, nitro, and amino; M is either magnesium or calcium.

2. The polypropylene β-nucleating agent according to claim 1, characterized in that: The polypropylene β nucleating agent is one or more of the following compounds:

3. A method for preparing a polypropylene β-nucleating agent according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1, raw material A and raw material B Heating in ethanol solution to prepare the compound of formula II S2, dissolving the compound of formula II in THF-MeOH-H2O, then adding LiOH . Heating with H2O gave the compound of formula III S3, mixing the compound of formula III with alkali solution, and adding alkaline earth metal salt solution dropwise under heating conditions to obtain the polypropylene β nucleating agent.

4. The method for preparing a polypropylene β-nucleating agent according to claim 3, characterized in that: In step S1, the molar ratio of the raw material A to the raw material B is 1:(1-1.2); and / or, in step S1, the heating temperature is 75-80°C, and the heating time is 0.5-2h.

5. The method for preparing a polypropylene β-nucleating agent according to claim 3, characterized in that: In step S2, the compound of formula II and the LiOH . The molar ratio of H2O is 1:(1-1.2); and / or, in step S2, the volume ratio of THF, MeOH and H2O in the THF-MeOH-H2O is 4:(1-2):(1-2).

6. The method for preparing a polypropylene β-nucleating agent according to claim 3, characterized in that: In step S2, the heating temperature is 45-50°C, and the heating time is 6-8 hours.

7. The method for preparing a polypropylene β-nucleating agent according to claim 3, characterized in that: In step S3, the heating temperature is 60-80°C, and the heating time is 2-4 hours.

8. The method for preparing a polypropylene β-nucleating agent according to claim 3, characterized in that: In step S3, the alkaline earth metal salt in the alkaline earth metal salt solution is one or more of alkaline earth metal nitrates or alkaline earth metal hydrochlorides; and / or, in step S3, the alkali solution is a sodium hydroxide solution.

9. The method for preparing a polypropylene β-nucleating agent according to claim 8, characterized in that: In step S3, the alkaline earth metal nitrate is calcium nitrate or magnesium nitrate, and the alkaline earth metal hydrochloride is calcium chloride or magnesium chloride.

10. A polypropylene material, characterized in that: The invention comprises the polypropylene beta nucleating agent described in any one of claims 1 to 2 or the polypropylene beta nucleating agent prepared by the preparation method described in any one of claims 3 to 9.

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